A hockey player practices n a frozen lake. The 0.166 kg puck initially sliding at .700 m/s stops sliding after 3.50 s. A) what is the average acceleration of the puck during this time? B) how far does it travel during this time? C) assume the puck stoped due to friction, calculate the coefficient of kinetic friction.

Respuesta :

Given:

• Mass, m = 0.166 kg

,

• Initial velocity, u = 0.700 m/s

,

• Time, t = 3.50 seconds

Let's solve for the following:

• (A). What is the average acceleration of the puck during this time?

To find the average acceleration, apply the motion formula:

[tex]v=u+at[/tex]

Where:

• v is the final velocity = 0 m/s

,

• u is the initial velocity = 0.700 m/s

,

• a is the acceleration

,

• t is the time = 3.50 seconds.

Plug in the values and solve for the acceleration, a.

[tex]\begin{gathered} 0=0.700+a(3.50) \\ \\ 0=0.700+3.50a \\ \\ 3.50a=-0.700 \end{gathered}[/tex]

Divide both sides by 3.50:

[tex]\begin{gathered} \frac{3.50a}{3.50}=\frac{-0.700}{3.50} \\ \\ a=-0.2\text{ m/s}^2 \end{gathered}[/tex]

Therefore, the acceleration of the puck during this time is -0.2 m/s.

The negative sign means the player was slowing down.

• (B). How far does it travel during this time.

To find the distance, apply the motion formula:

[tex]s=ut+\frac{1}{2}at^2[/tex]

Where:

s is the distance travelled.

u is the initial velocity = 0.700 m/s

a is the acceleration = -0.2 m/s²

t is the time = 3.50 s

Thus, we have:

[tex]\begin{gathered} s=0.700(3.50)+\frac{1}{2}(-0.2)(3.50)^2 \\ \\ s=2.45-1.225 \\ \\ s=1.225\text{ m} \end{gathered}[/tex]

Therefore, the distance traveled during this time is 1.225 meters.

• (C). Assume the puck stopped due to friction, calculate the coefficient of kinetic friction.

To calculate the coefficient of kinetic friction, we have:

[tex]ma=\mu mg[/tex]

Where:

m is the mass = 0.166 kg

a is the acceleration = -0.2 m/s²

g is the acceleration due to gravity = 9.8 m/s²

μ is the coefficient of kinetic friction.

Thus, we have:

[tex]\begin{gathered} \mu=\frac{ma}{mg} \\ \\ \mu=\frac{a}{g} \\ \\ \mu=\frac{0.2}{9.8} \\ \\ u=0.0204 \end{gathered}[/tex]

Therefore, the coefficient of kinetic friction 0.0204.

ANSWER:

• (A). -0.2 m/s²

• (B). 1.225 m

• (C). 0.0204